Renewable energy movement pushes storage tech

Midwest Renewable Energy Association at the annual renewable energy festival, stressed on storage technology, calling it the "Holy Grail" of the renewable energy movement. One such star technology was lithium-ion battery, according to experts, which is slowly making the transition from a power source for electronic devices to the primary power storage technology for hybrid vehicles and low-maintenance backup power at remote sites like cell towers.

While much of the focus has been on the latest engineering innovations in lithium-ion battery technology, the grassroots "personal power" movement symbolized by energy fairs like this one has more to do with what consumers can get their hands on now, said energy consultant Randy Richmond, founder of RightHand Engineering.

"What's innovative for a typical user is different than what it might be for an engineer," said Richmond. Hence, the biggest innovation is the availability of cheaper products like lithium-ion batteries from China. "It's innovative that I can get this stuff [and] it's cheaper."

Batteries based on chemistries like lithium iron phosphate are available now, "but the equipment necessary to use it on a residential renewable energy system doesn't exist yet," Richmond said. "I think it will happen, but the manufacturers I talk to are just now beginning to think about it."

Widespread commercial availability of lithium-ion battery technologies for renewable energy applications such as hybrid cars remains several years off, experts here predicted. Among the reasons are the entrenched market for lead-acid batteries and the high upfront cost of investing in lithium-ion technology.

"It probably will be three years before we start seeing equipment available that will make use of the batteries that are available today," Richmond said. "And of course the battery technology will improve, and probably three years from now we'll see something better than we've got now."

Among the emerging technologies are lithium air and nanotube carbon technologies. The latter could be used in combination with different battery chemistries. "It may triple what lithium ion does today," Richmond predicted, but will bring it with it a new set of problems like adapting charging control equipment.

Richmond's small company sought to demonstrate the potential returns of investing in the emerging battery technology by converting a 2001 GMC pickup truck to an electric vehicle. He replaced the truck's lead-acid battery with a battery pack consisting of 48 3.3V lithium iron phosphate batteries placed in the truck's bed. The result of the roughly Rs.6.56 lakh ($12,000) investment was a doubling of the truck's range and acceleration.

One issue was consistent charging of all the batteries. Hence, Richmond said he invested an additional Rs.1.75 lakh ($3,200) in a battery management system to avoid over- or undercharging.

Projects like converting vehicles from internal combustion engines to electric drives are demonstrating the commercial viability of emerging battery technologies, but what about the larger potential of renewable energy to meet future U.S. energy demand? A study released last week by the National Renewable Energy Lab forecasts that current renewable energy sources combined with a more flexible power grid could supply as much as 80 per cent of total U.S. electricity generation by 2050.

A key enabling technology for achieving that goal, the study found, was improved "grid storage."